The pristine sample in the presence of CO2 presented peaks in the region from 1681 to 1650 cm−1 , which may be assigned to adsorbed CO2 coordinated to the compensation cation (Na+) in bidentate form, and around 1361 cm−1 in monodentate form [24]. In the case of ZX10, other observed bands account for unimpeded carbonate ion in the range of 1420–1450 cm−1 [21].